The Kenwood SP-230 external speaker is an upgrade to the built-in speaker for various Kenwood HF rigs. Similar to my Yaesu FT-991A, the Kenwood HF rigs I have use a small internal speaker just under top cover for the built-in speaker. The audio quality of these internal speakers are limited in my opinion mainly due to the fact that they are facing upward and not forward toward the operator

Simply moving a speaker to face forward makes a significant difference in sound quality. This is why almost any external speaker which is front facing will improve the sound quality and experience for the operator.

The SP-230 is designed to match the TS-830 and also matches the TS-530. The speaker cabinet itself is large, the same height as the rigs they match. This allows for a larger than average driver size and quite a bit of room for acoustic properties to improve sound quality versus a smaller cabinet size.

The SP-230 speaker cabinet has an A/B switch, allowing for connection to two rigs and to be able to switch between them. It also has a low filter and two high filters. These filters can be combined if needed. Adding this speaker made quite a difference, however the speaker itself is rather cheap.

Since the speaker inside the SP-230 is rather cheap, the sound quality can be improved quite a bit. My experience with this external speaker from Kenwood was similar to my Yaesu SP-10 external speaker. I had purchased the SP-10 external speaker for the FT-991A and found that its internal driver was no different from the internal speaker built into the radio. The only real difference is that the speaker is front facing versus the top facing speaker in the radio. I found the Phonema PHITS acoustic foam kit which was designed for the SP-10. It made such an improvement combined with a driver replacement I found on Amazon.

Gamma Phits GPH-X80 and Phits K95A

I purchased a similar kit for the SP-230, the Phits K95A. This is the acoustic foam kit designed to fit the SP-230, SP-930, SP-940, and SP-180. I also found the Phits GPH-X80, which is the speaker driver replacement for the SP-230, also fitting the SP-180 and Yaesu SP-767 and SP-102.

I replaced the speaker first. It was very easy to replace and everything lined up perfectly. I took the front plate off so that there was a bit more room to get the soldering iron in there. The positive connection to the speaker was just long enough to reach, so I avoided cutting too much off the end when clipping out the old speaker. There are two connections to the negative side of the speaker.

I was impressed to see a real filter circuit in this speaker. Notice how this circuit is bolted to the lower cover with short standoffs.

After replacing the speaker, I started adding the foam. The most difficult part of the process is the bottom piece of foam. I had to remove the filter circuit from the bottom cover, and remove the standoffs from the bottom cover.

The kit comes with 4 new taller standoffs. These can then be punched through the foam and the filter circuit placed higher up off the bottom cover. I used a small screwdriver from underneath the bottom cover to punch through the foam, then push (while twisting) the standoffs back down through the foam.

After adding the two foam pieces on the side and the foam piece on top, I found it to be quite a challenge to get the top cover back on. I had the exact same challenge with the SP-10 foam kit. I carefully pushed down on the top cover and placed one screw at a time until all of the screws were in place.

Results

The new speaker and foam sounded great! At first it had way too much high end, almost tinny. What I found was I had to turn the tone dial on the rig all the way to the right with the original speaker. With this replacement, the tone dial in the middle sounds best.

I just so happened to pick up a pile up on 10 meters with a station in the UK. I was able to pick out quite a few of the call signs with ease. The replacement was a success and made quite a difference.

As with any modification, I attempt to avoid permanent changes to vintage equipment. I saved the original speaker and standoffs, and can easily revert back to the original configuration if needed.